He won the Eclipse at Sandown even after having to overcome the team attentions of the Aidan O'Brien stable while in the Juddmonte International at York he beat six other group one winners, bolting in by three-and-a-quarter lengths.
His Irish Champion Stakes win also saw him conquer six other group one performers while he capped his home season by adding the Queen Elizabeth Stakes at Ascot, a race his champion trainer John Gosden thought might be beyond him because of the conditions.
"He has proven his class and his guts to get there," said Gosden after the Ascot win.
"Because I think he was hating every second of running on that (heavy) ground. You could see from his action and the way he was carrying himself.
"I would not work him on that ground."
Roaring Lion was retired soon after and is standing his first Northern Hemisphere season at Tweenhills Stud at £40,000 ($77,500), making his Cambridge fee of $35,000 an enormous discount for Southern Hemisphere breeders.
And he should provide plenty of Australasian breeders with an attractive outcross option, being free of Danehill blood.
The Lindsays have appointed respected thoroughbred expert Henry Plumptre as their chief executive at Cambridge Stud and he can hardly believe their luck in being able to attract two of Europe's elite racehorses to stand at the legendary Waikato farm in such a short time frame.
"To be able to secure two European Champions in two years is extraordinary and very exciting," said Plumptre. "Roaring Lion is hugely sought after in the UK in his first season at stud and even standing at £40,000 he is oversubscribed.
"His sire, Kitten's Joy, is the reigning champion sire in the USA and has been champion turf sire for the past six years.
"By El Prado, he has a similar profile to the champion Medaglia D'Oro, also by El Prado, who sired Vancouver, Astern and the recent NZ Derby winner Crown Prosecutor."
Roaring Lion's addition to the stallion ranks comes at a time when Cambridge Stud are redeveloping parts of the historic property and when the Lindsays are riding the crest of a wave with their own racehorses after significant domestic investment.
That could reach a new zenith on Saturday when their champion two-year-old filly Probabeel contests the A$1 million Sires' Produce at Randwick for which she is rated a $9.50 chance.
King of the jungle
• World champion three-year-old Roaring Lion is a big-name addition to the New Zealand stallions ranks.
• He will stand at Cambridge Stud.
• Roaring Lion won four group one weight-for-age races in Europe last year.